Pump



L. T. STOYKE PUMP Filed Dec. 16, 1953 Aug. 20, 1957 7 fi 6 i a. r I W! VUnited States Patent PUMP Ludwig T. Stoyke, Rockford, Ill., assignor toSundstrand Machine Tool Co., a corporation of Illinois This inventionrelates to pumps and more particularly to a means for preventing hum orvibration during pump operation.

It is the general object of this invention to provide a new and improvedfuel pump having improved means for eliminating hum or vibration.

I A further object is to provide a fuel pump with an antihum devicewhich is easy to manufacture, of simple construetion and easilyinsertable and replaceable in a pump.

Another object is to provide a fuel pump embodying a casing with areservoir portion to which the intake of a pumping mechanism opens, aremovable closure, a pumpmg mechanism end plate for the reservoir and anantihum device associated therewith.

Another object is to provide a fuel pump such as described above with anair-tight diaphragm embodying two thin nylon plastic halves of flexiblethin-walled construction sealed together to form an air spacetherebetween and means associated with the fuel pump intake reservoirfor releasably supporting the diaphragm on the pumping mechanism endplate so that said diaphragm may be easily snapped into or out ofposition.

Another object is to provide an anti-hum device for such a fuel pumpincluding a diaphragm as described above and a retainer thereforembodying a ring mounted on the reservoir side of the pumping mechanismend plate and having a plurality of spring teeth for releasablyrecelving the diaphragm, the end plate having a recess adacent thediaphragm so that said diaphragm is positioned in the pump intakereservoir in a spaced relation from the end plate and has its entireexternal surface area immersed in fuel in the reservoir.

Other and further objects of the invention will be readily apparent fromthe following description and drawings in which:

Fig. 1 is a longitudinal, vertical section through a pump showing thepreferred form of the invention;

Fig. 2 is a fragmentary view approximately along the line 22 of Fig. 1;and

3 is a sectional view taken along the line 33 of While this invention issusceptible of embodiment in many different forms, there is shown in thedrawings and will herein be described in detail an illustrativeembodiment of the invention with the understanding that the presentdisclosure is to be considered as an exemplification of the principlesof the invention and is not intended to limit the invention to theembodiment illustrated. The scope of the invention will be pointed outin the appended claims.

In the form selected for purposes of disclosure, the invention isembodied in a fuel pump of the type disclosed and claimed in Patent No.2,232,983, dated Feb ruary 25, 1941. As illustrated in Fig. 1, a fuelpump consists generally of a two-part casing 10, 11, a pumping device ormechanism 12, a drive shaft 13, a mechanical seal 14 for the driveshaft, and a strainer 15. A control valve mechanism 16 forms no part ofthe present invention but may be of any appropriate type suitable foruse with an oil burner type fuel pump. It is contemplated that the shaft13 will be connected by suitable means to a driving motor (not shown),and that an inlet port 17 will be connected to a source of fuelsupply'such as a tank (not shown).

The casing parts 10 and 11 are formed to provide a somewhat cylindricalrecess or reservoir 18 in which the pumping mechanism 12 and strainer 15are positioned. The pumping mechanism generally consists of anexternally-toothed roller 19 secured to the shaft 13 by a pin 20, aninternally-toothed ring gear 21 having the lower portion thereof meshingwith the roller 19 and an intermediate crescent guard 22. The completedetails of this mechanism are disclosed in said prior application andfunction in a well-known manner to draw fuel into the inlet port 17,through the chamber 18 and in through the intake port 22a- (Fig. 2) inthe pumping mechanism end plate 24. Upon rotation of the shaft 13 in aclock- Wise direction, the fuel is carried in the cavities of the rollerand ring past the crescent guide 22 then forced out through a dischargeport (not shown) and is conducted to the outlet valve mechanism 16 andfrom said valve mechanism it passes either through suitable meansadapted for connection to an oil burner or through a by-pass port 26(Fig. 1) operable to allow return passage of fuel to a fuel tank whenthe plug 27 is removed and a return conduit connected therein. Thestrainer 15 is generally cupshaped and has adjacent ends 28 and 29positioned on casing part 10. The strainer surrounds the pumpingmechanism so that all of the fuel entering the inlet port 17 must passthrough the strainer to reach the pumping mechanism 12.

In an oil burner installation an objectionable hum or vibration issometimes encountered during operation of the pumping mechanism and,unless absorbed, will be transmitted to the fuel line and supply tank.In order to eliminate this hum or vibration, a closed air pocket 31 isformed in a portion of the recess or pump inlet reservoir 18 to absorbany pulsations set up in the pump before they are transferred to thefuel line or tank.

As illustrated in Figs. 1, 2 and 3 the air pocket 31 is provided by adiaphragm 32 removably supported by a retainer assembly comprisingspring teeth 33 fixed to ring 34 which is mounted on the reservoir sideof end plate 24 by screws 35. A recess or cavity 36 is provided in theend plate 24 adjacent the diaphragm 32 so that the diaphragm is in aspaced relation from the end plate and has it entire external surfacearea immersed in fuel in the reservoir 18.

The diaphragm 32 comprises two flexible sides 37 each side having aslightly concave outer face portion 38 and circumferential convex edgeportion 39 circumscribing a hollow body portion, the diaphragmterminating in a substantially flat circumferential flange portion 40.The sides are of flexible thin wall construction formed of any suitablematerial and in a preferred construction consist of die molded nylonplastic material. The molded sides may be fixed together by use of aheat sealing machine which, when the proper amount of heat is applied,causes the edge portions 40 to become permanently fused and sealed,leaving an air space in the body portion and giving the body portion thegeneral shape of a unitary hollow plastic button.

Prior attempts to prevent hum or vibration have embodied the use ofclosed air chambers but they have proven difiicult to seal and check forair tightness, not easily removable or replaceable and the anti-humqualities have not been utilized to the maximum extent possible. Thesimple and compact construction of my anti-hum device enables it to bereadily and inexpensively produced. The retainer assembly allows thediaphragm to be quickly replaced by snapping it into or out of positionin the pump fuel reservoir and its unitary construction facilitates easytesting for air tightness prior to installation. The end plate andretainer assembly are constructed and arranged to position the diaphragmin a spaced relation from the end plate so that the entire externalsurface of the air pocket is immersed in fuel to insure maximumutilization of its anti-hum qualities.

I claim:

1. A fuel pumping device comprising, a casing having inlet and outletports, a recess in said casing communicating with the inlet port,pumping mechanism positioned in said recess and operable to draw fuelfrom the recess and force it out the outlet, a removable cover plate forsaid recess, an end plate for said pumping mechanism positioned in saidrecess and having a cavity opening into the recess, a metal ring mountedon said end plate and carrying a plurality of spring teeth adjacent theperiphery of said cavity, a hollow button-shaped diaphragm of nylonplastic material with spaced flexible walls defining a body portionproviding a closed air chamber between said walls, said body portionhaving a diameter less than the diameter of the cavity and saiddiaphragm having its edge portions releasably secured between the springteeth and adjacent surface of the end plate and its body portionpartially disposed within the cavity and in spaced relation from the endplate, the construction and arrange- A ment being such that the entireexternal surface area of the flexible walls defining said closed airchamber is positioned to be immersed in the fuel in said recess.

2. A fuel pumping device comprising, a casing provided with inlet andoutlet ports, a recess in said casing communicating with the inlet port,pumping mechanism positioned in said recess and operable to draw fuelfrom the recess and force it out the outlet, a diaphragm of nylonplastic material comprising two flexible sides and a circumferentialedge portion terminating in a substantially flat circumferential flange,the sides being sealed together along said flange to define a bodyportion providing a closed air chamber therebetween, and resilient meansin said recess position to engage the flange for securing said diaphragmtherein, said resilient means detachably securing said diaphragm in therecess, the construction and arrangement being such that the entireexternal surface area of the flexible walls defining said body portionis positioned to be immersed in the fuel in said recess.

References Cited in the file of this patent UNITED STATES PATENTS2,232,983 Wahlmark Feb. 25, 1941 2,311,916 Wahlmark Feb. 23, 19432,418,667 Rockwell Apr. 8, 1947 2,512,765 Byram June 27, 1950

